In order to examine an operation form in iron manufacture remains of the ancient times, We extracted the carbon which was inherent in an iron sample in high purity and we were highly precise and had to do sample adjustment. Therefore, We developed combustion / CO_2 separation / a refinement line of the sample which could remove possibility of pollution by modern carbon as much as possible. And the carbon extraction efficiency more than 90% led a combustion condition to be provided even if I put it when there were a little carbon contents. As a result, I get possible to get ^<14>C age without pollution by modern carbon.In addition, I did the radiocarbon dating with an accelerator mass spectrometry of the excavated iron sample which I could grasp of a generation value of archeology of remains, They showed the age the same as the index remains which showed an age of archeology of remains. It became clear to come from the charcoal which I used at the time, and the carbon history of iron remains excavated by these results of research was able to confirm legitimacy and the effectiveness of what radiocarbon dating of being made of iron remains measured.However, on the other hand, various examination problems occurred. A remarkable thing is for a time difference to be watched in charcoal and ^<14>C age used for iron manufacture of iron generated thereby among other things. It is supposed so that there is rule nature of a certain degree in a difference between this time. Furthermore, In forging steel, The δ ^<13>C showed a value bigger than representative δ ^<13>C of the charcoal which was the cause of a carbon origin in the iron material, and it became clear that carbon isotope discretion could be generated.